On Tue, 27 Aug 2019 16:20:17 +0100, (Roger Hayter)
wrote:

snip

[1] Like the rubber bushing you get in the bolt up BNC connectors and
the like.

Where I need a sealant for *plastic* threads, or plastic to metal, I've
found Fernox LS-X is much better than PTFE tape, which tends to extrude
itself from plastic threads.

I'll check that out.

I would be interested in what people use to seal the waste to the top of
such things as shower trays. Plumber's mait can be gradually washed out
if the edge of the waste is cleaned too fastidiously, and can look
smeary if it isn't.

I think I've generally used clear silicone, masking the area prior to
application helping give a clean result (tape down first, cut round
with a scalpel, remove fitting and inner tape, seal, fit and trim /
peel outer tape when it's cured slightly).

If the hole is recessed enough and the outer diameter of the flange
pretty close, I might just silicone up to the hole / flange.

Cheers, T i m